Power angle control of grid-connected doubly fed induction generator wind turbines for fault ride-through

This study proposes a power angle control strategy of grid-connected doubly fed induction generators (DFIGs) to improve the transient performance during grid fault ride-through (FRT). The proposed power angle control can efficiently restrict the rotor-side current under a limited converter rating, support the terminal voltage of DFIGs and hence improve system stability during the fault period. In this study, the power angle of DFIGs in a multi-machine power system is defined firstly and then the relation between the defined power angle and rotor-side current surge and terminal voltage dip of DFIGs are analysed, respectively. Based on the analysis, control of DFIG power angle is implemented expediently on the existing flux magnitude and angle control (FMAC) scheme of DFIGs as an improved FMAC scheme. In this study, two test examples are presented to demonstrate and validate the effectiveness of improved FMAC with power angle control and to compare it with the conventional PQdq control and FMAC. Simulation results show that it can significantly enhance the FRT capability of grid-connected DFIGs.